Combined bms, charger, and dc-dc in electric vehicles

ABSTRACT

A controller of an electric vehicle is disclosed. The controller includes: a BMS LV module configured to manage a low voltage battery; a BMS HV module configured to manage a high voltage battery; a DC-DC module configured to control a plurality of DC-DC FETs; and an ampSwitch module configured to detect a short on a bus and switch to an open state, and further configured to command the DC-DC module or an alternator to match the low battery&#39;s voltage and switch to a closed state when voltage returns to normal.

FIELD OF THE INVENTION

This relates to systems for electric vehicles and, more specifically, toa combined Battery Management System (BMS)/Charger/Direct CurrentConverter (DC-DC).

BACKGROUND OF THE INVENTION

The advent of mainstream electric vehicle and e-mobility application(like vertical take-off and landing (VTOL) helicopters and e-bikes)adoption requires a fresh perspective regarding the architecture of theelectrical power system. Previous attempts at electric vehicles haveresulted in sourcing individual electrical components that providespecific functionality and are distributed across the vehicle. Theattempt from suppliers of electrical components has been to produce ageneric component to be used across multiple vehicle lines in order toreduce cost through economies of scale. This disclosure provides asolution of reducing non-recurring engineering (NRE) and bill ofmaterial (BOM) cost, volume and mass through integration of individualcomponents while providing added features.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an electrical diagram of the BCD, according to an embodimentof the disclosure.

FIG. 2 is a block diagram illustrating the exemplary components of powerelectronics.

FIG. 3 is an exemplary cell voltage waveform demonstrating ripple whilecharging, according to an embodiment of the disclosure.

FIG. 4 illustrates a side view of a BCD (i.e., ampBCD), according to anembodiment of the disclosure, compared to a traditional OBC and DC-DCcombination.

FIG. 5 provides an external view of an BCD, according to an embodimentof the disclosure.

FIG. 6 provides another view of the BCD of FIG. 5, according to anembodiment of the disclosure.

FIG. 7 provides an internal view of the BCD with the top PCB removed,according to an embodiment of the disclosure.

FIG. 8 provides a partial view of the BCD showing a current shunt deviceand a fast charge contactor thermally coupled to a cold plate, accordingto an embodiment of the disclosure.

FIG. 9 provides another partial view of the BCD showing large powermagnetics components coupled to cold plate using square wire, accordingto an embodiment of the disclosure.

DETAILED DESCRIPTION I. Acronyms and Definitions

-   BMS—Battery Management System-   BOM—Bill of Materials-   Contactor—mechanical or solid-state switch electrically isolating    connection point(s)-   DC-DC—Direct Current Converter-   IBS—Intelligent Battery Sensor for the LV BMS function-   LV or LVB—Low Voltage battery or system. Typically, in automotive,    12V, 14V, 16V, 24V, 42V, 48V, but not so limited-   HV or HVB—High Voltage battery or system-   isoSPI—isolated communications typically used for HV battery cell    voltage and temperature measurements-   NRE—Non-Recurring Engineering-   OBC—On Board Charger and/or wireless charger-   BCD—Combined BMS/Charger/DC-DC (the term “ampBCD” refers to an    embodiment of the BCD in the present disclosure)-   PTC—Power Train Controller to determine motor torque to 1 or more    motors in the system-   V and T—Voltage and Temperature measurements-   SOC—State of Charge-   CAN—Controller Area network-   ASIC—application-specific integrated circuit-   FET—Field Effect Transistor-   IGBT—insulated-gate bipolar transistor-   SPI—Serial Peripheral Interface-   HVIL—High Voltage Interlock Loop

II. HV Architectures May Contain One or More of the Following Components

1. The high voltage distribution box (ISO15118/GBT charging controller,fast charge contactor control)

2. High-voltage BMS

3. Low-voltage BMS typically required if redundant 12V (or other LV) isneeded

4. On Board Charger—

5. DC-DC 1 typically required if redundant 12V (or other LV) is needed

6. Powertrain Controller

7. Smart Fuse Box

8. 12V (or other LV) Battery contained in BCD

In this document, the term “12V” is not limited to a 12V battery, but isrepresentative of any LV.

Embodiments of this disclosure combine these systems, which also addsseveral new features so the following benefits can be realized asdescribed in the table below. Since the components are integrated into asingle unit, much of the harnessing required (both HV and LV) is reducedsignificantly as these connections can be made via internal bus bars orPCB traces depending on the power requirements. Furthermore, safety andreliability can be increased with a reduction of the amount of externalconnections between individual components. A subset of combinations canalso be realized in other embodiments of the disclosure. Notice how thedisclosed embodiments have virtually eliminated one junction box in thevehicle from the diagram in the table below.

III. System

Described below, with reference to FIG. 1, is an embodiment of thedisclosed BCD system 100 with a number of components. As illustrated,the BCD 100 of FIG. 1 can include a LV sensor (or “Sensor LVB”) 102connected to a LV (e.g., the 12V battery 104 as shown in FIG. 1), asingle DC-DC 106, a main controller 108, a HV battery contactors 110connected to a HV 112 (not part the BCD 100), a bi-directional OBC 114,and FC contactors 116. The bi-directional OBC 114 and the FC contactors116 are connected to a charge connector 118 external to the BCD 100 viaAC 150 and DC 152 connections, respectively. The charge connector 118can, for example, be one of a combined charging system (CCS), GB/T,CHAdeMO, and a wireless transformer. The bi-directional OBC 114 and theFC contactors 116 are also connected to the HV 112 via the HV Batterycontactors 110. The single DC-DC 106 connects the LV sensor 102 with theHV battery contactors 110 and the FC connectors 116.

The LV sensor 102 can include multiple iSensors 140, 142, 144 on variouslocations of the electric paths as shown in FIG. 1. The LV sensor 102can also include an isolation switch 138 can connect and disconnect oneof the out connections 160 to the LV (12V) 104. The out connection caninclude an optional fuse 162. The LV sensor can also include an optionalfuse and contactor 148 connecting to the in connection of the LV (12V)104. The exemplary functions of the above-listed components of the BCD100 will be described below in Table 3.

The main controller 108 includes various modules including a LVBMS 122,a HVBMS 124, an OBC 126, FC 128, PTC 130, DC-DC 132, Amp-switch 134, andanalog-to-digital converter (ADC) 136. The LVBMS 122 manages the LV 104.These modules of the main controller 108 can be implemented in firmware,hardware, or both, and are in communication with the components of theBCD that are under their respective control and/or management. Theexemplary functions of each of these modules are discussed in Table 4below.

In some embodiments, some of the components can be optionally andexcluded from the BCD 100. For example, the HVBMS 124 or the PTC(Powertrain Controller) 130 may live elsewhere in the vehicle system.Also, note that the bi-directional OBC (On Board Charger) 114 can beuni-directional depending on user requirements. Some users, who do notcare about autonomous Level 3+ requirements, may not need the ampSwitch.Also, note multiple HV out connections (collectively as 130) can be madeto other HV components not included in the disclosed embodiments of BCD100, like the drive inverter or PTC heater (not shown in FIG. 1).

For the LV (12V) side, there can be up to 4 legs of current flow. TheBCD 100 only needs 3 current sensors (e.g., iSensor A 140, iSensor B142, iSensor HVB-A 146) at arbitrary locations per Kirchhoff's law. TheampSwitch 134 can live on its own (e.g., outside of the BCD 100). Itshould be noted that fuses can be optional. This is dependent on thefailure mode of the LV (12V) battery.

IV. Electrical

Consolidation of the high-level power controllers enumerated aboveyields cost, weight, and volumetric efficiencies. Electromagneticinterference filter (EMI) filtering components, power supply components,FR4 and other Printed Circuit Board Assembly (PCBA) materials,connectors, processors, and processor peripheral devices are sharedbetween the different controllers such that the system in total containsfewer of these components. Additionally, the reduction of PCBA systemsreduces total system labor and production overhead such as end of linetesting and conformal coating.

The electrical diagram has the following I/O:

TABLE 2 Electrical Inputs and Outputs Electrical Connection Purpose 12 VIn 170 To be able to manage the low voltage battery 12 V Out(s) 172 12 VOutput source A, B, C . . . Vehicle CAN 174 Communication to the vehicleJ1772/PLC/CAN 176 Communication to the charger Pedal Monitor 178 Directhigh-speed communications to the pedal. This could be analog or SPIcommunications that monitor the accelerator and brake pedal AC/DC 150,152 Power transfer to connector HV In(s) 182 High voltage batteryinput(s) HV Out(s) 184 High voltage battery output for the driveinverters, PTC Heater, heating, ventilation, and air conditioning(HVAC), wireless charger etc.

The internal components are described in the table below:

TABLE 3 Electrical Hardware Electrical Hardware Components PurposeiSensor LVB To be able to measure current of the LV battery 102 104 forthe following purposes: 1. SOC estimation of the LV battery 104 2.Safety protection of 12 V 104 to detect short circuit via a hardwarecomparator circuit 3. Charge and discharge manager of LV battery 104 tomaximize life Ideally this is a shunt, because it can be thermallymanaged and packaged better. This can be a hall- effect or flux gate insome lower current appli- cations (<500 A). iSensor A 140 To detect ashort-circuit failure of the 12 V A bus. This can be a hall-effect orflux gate in some lower current applications (<500 A). iSensor B 142 Todetect a short circuit failure of the 12 V B bus. This can be ahall-effect or flux gate in some lower current applications (<500 A).ISensor HVB To be able to measure current of the HV battery for 146 thefollowing purposes: 1. SOC estimation of the HV battery 104 2. Safetyprotection of short circuit via a hardware comparator circuit. Ideallythis is a shunt, because it can be thermally managed and packagedbetter. This can be a hall- effect or flux gate in some lower currentappli- cations (<500 A). ampSwitch A solid-state switch comprised ofback-to-back FETs. (HW Compo- SiC can be used. If the hardware circuitsof the nent) 134 iSensor A, B or LVB 140, 142, 146 detect a shortcircuit, this switch will open. Only the micro- controller can reclosethe switch after it verifies the short circuit condition has gone away(see FW section). J1772/PLC/ Communication to the charger. J1772/PLC isused in CAN 118 the US and Europe. CAN is used via the GBT and CHAdeMOstandards in Asia Bi-Direc- This could be uni-directional as well. It istional typically 3 to 19 KW of power. The core can drive the OBC 114gates of the OBC either digitally or via power electronic control ASICs.FC Con- Fast Charge contactors which function to prevent tactors 116exposing HV to the Connector pins when not plugged in Single DC- Chargesthe 12 V battery 104 from the HV battery 112 DC 106 LVB V and Voltageand temperature readings from the low voltage T 175 battery 104. Forlead-acid batteries this is typically a Kelvin measurement of the entiremodule monitoring a single terminal temperature, typically on thepositive electrode. This can be direct measurements or communicated overvia LIN isoSPI 177 Communicates cell, brick, pack/string currents, packvoltage, bus voltage and module voltage of the battery pack. Alternativecommunication means to HV battery packs exist from TI and Maxim andothers. Main Monitors and controls the BCD system 100 via a pre-controller ferred lock-step core that is at least ASIL B rated. 108 Seefirmware section for more details

V. Firmware

Below is a list of firmware components that live in the main controller108. Note that some of these functions can be optionally implemented inhardware or a combination of firmware and hardware. The main controllershould be above 180 MHz and be able to control all these functions. Amulti-core processor is desirable.

TABLE 4 Firmware (or Hardware) of the Main Controller 108 FirmwareComponents Function BMS LV 122 Using the LVB V and T 175, and iSensorLVB 102, manages the low voltage battery for health, safety(over-charge/discharge), controls charge/discharge limits, and estimatesSOC. BMS HV 124 Using the HVB V and T 175, and iSensor HVB 146, managesthe high voltage battery 112 for health, safety (over-charge/discharge),controls charge/discharge limit, thermal limits, and estimates SOC, andother typical function of a HV BMS 124. OBC 126 Controls the OBCFETs/IGBT by referencing a current setpoint provided by the wall-powerlimit and the battery limit. Could be conductive and/or wireless. FC 128Manages opening/closing the FC contactors 116 with diagnostics for welddetection. PTC 130 Determines appropriate torque limits of thepowertrain system to control both longitudinal and lateral movements ofthe car. The main advantage in putting the PTC function in the BCD 100is that the iSensor HVB 146 is directly measured. Knowing this, thepowertrain can be controlled without over-discharging or“over-regenerating” the battery pack. For high powered systems (i.e.Tesla Model S Ludicrous) this is essential as it allows maximumpowertrain power without sacrificing battery life. DC-DC 132 Controlsthe DC-DC FETs. Because the low-voltage battery is managed here, the BCD100 can ensure that over-charge will not occur in a functionally safemanner. This is an advantage over other disconnected systems, whichrequire an additional contactor to achieve this function. ampSwitchOpening of the switch will be done in hardware. The firmware (block 134)(firmware)134 will determine when to safely close the switch. 1. TheampSwitch 138 will detects a short on either bus by detecting a voltagedrop on either Bus A or Bus B (a controller or simple comparator can beused) or using a comparator of the current sensor outputs. When thishappens, the switch 138 will be commanded to open by either the hardwarecircuit of block 134. 2. When voltage returns to normal (>10 V), theampSwitch 138 will command the DC-DC or alternator to match thebattery's voltage. At that point the switch 138 will be re-closed. 3.Optionally, a shunt or hall-effect current sensor can be used to detecta short. 4. To reduce heat accumulation and keep the switch fromfailing, the switch will be mounted to the aluminum cold plate/heatsinkfor improved cooling. 5. The accumulation of these ideas can be used tocreate a simple device that enables redundant low voltage powersupplies. By utilizing both current and voltage measurements, the systemis more robust and can act quicker than other similar systems. ADC 136This module will directly monitor analog signals and employee digitalfilter techniques for the following signals: 1. iSensor X 140, 142(alternatively, SPI or i2C can be used). This is an advantage of the BCD100 as it can avoid an expensive CAN-based current sensor. Since thecontroller will be packaged near the sensor, EMI is less of a concernand direct analog measurement can be used. 2. Low voltage batteryvoltage and temperature sense. 3. Pedal monitor position signals of bothbrake and accelerator pedal.

VI. Power Electronics

The combination of the OBC and the DC-DC into a common physical packagepresents a novel way of creating a single power electronics topology toservice the requirement that both the OBC and DC-DC provide separately.This can be realized by combining the power magnetics of both convertersinto a single package.

An OBC must step up the input ‘mains’ voltage of 110 or 220 VAC tonearly 800 VDC at the battery pack. Because of the increasing losseswith increasing input/output gain in a boost topology, a high frequencytransformer is utilized in place of a traditional boost converter tostep up the voltage. This make galvanic isolation inherent to anefficient OBC. Likewise for similar reasons, a high frequencytransformer is utilized in place of a single stage buck converter tostep down the voltage in a DC-DC converter. The high frequencytransformer used in the DC-DC can be eliminated by adding a tertiarywinding to the transformer of the OBC. Doing this also eliminates thededicated power silicon drive circuitry for the DC-DC transformer. Notethat while utilizing the transformer of the OBC for the DC-DC, the DC-DChas two energy sources, the HV battery pack and the AC ‘mains’ sourcewhile the vehicle is plugged in and charging. This is demonstrated incircuit block diagram of FIG. 2.

In FIG. 2, the top row represents the OBC 200, with power flow from theAC ‘mains’ 202 on the left to the battery pack on the right. To reducethe size of the transformer core, the transformer is being driven inboth directions to double the flux swing by H-bridge “H1” 208. H-bridge“H2” 212 is a full-bridge active rectification stage followed by a lowpass LC filter 214, 216 before the HV battery 218. The second rowrepresents the DC-DC 220, which consists of full bridge rectification inH3 222 with a LC low pass filter 224, 226 on the output. The DC-DC 220is bi-directional and that allows a second feature to pre-charge thehigh voltage bus. Normally, the BMS has a precharge relay. Thisprecharge feature comes for free.

There are two modes of power flow for this topology that correspond towhen the vehicle is charging and when it is driving. While the vehicleis charging, the LV power bus is supplemented by the DC-DC 220 from thetertiary winding of the OBC transformer. While the vehicle is not incharge mode and is driving the energy source of the DC-DC 220 is thenswitched to the HV battery system. In this mode of operation, inductor“L1” 214 is decoupled by reverse flow of current (through the diodes ortransistors around L1 214), and bridge “H2” 212 used previously forsynchronous rectification is now used as the driving circuitry of thetransformer.

When combining, the OBC 200 and the DC-DC 220 into a unified powerelectronics topology, nearly half of the power electronic and magneticcomponents of the DC-DC 220 are eliminated.

Traditional chargers and DC/DC converters have large output capacitanceto minimize current ripple. Current ripple is important to control intraditional systems because the BMS (which regulates charge current) isnot integrated and looks at a filtered average current (FIG. 3). In thecombined system the BMS can sample the cell voltages at the peaks of thewaveform ensuring that we do NOT overcharge the battery, and each cellvoltage never rises above its maximum limit. This allows us to reducethe output capacitance by, for example, 20 to 50%. The system knows whento sample the cell voltages at the peaks of the waveform because thevoltage sample trigger is synthesized from the OBC's H-bridge PWMcarrier frequency, which is all combined into a single system.

VII. Mechanical

When the OBC and DC-DC are packaged in the same enclosure, they canshare a common cold-plate (water-cooled heat sink). In addition, knowingthat the DC-DC and OBC will never be fully on at the same time andgenerating maximum heat, the shared cold-plate can be downsized. Whencharging, the DC-DC doesn't need to provide power for heated seats,powered steering, ABS, stability control, etc. which can be severalhundreds of watts of additional heat loss. And conversely, when the caris driving and needs the above functions mentioned above, the OBC isoff. Therefore, by combining the DC-DC and OBC the heat-sink is reducedin size. FIG. 4 illustrates the two points made above. The traditionalseparate OBC and DC-DC set-up 400 is illustrated on the left. Thetraditional set-up 400 requires a cooled cold plate 408 for the OBD 402and a second cooled cold plate 410 for the DC-DC 406 that is separatefrom the OBD 402. In contrast, the BCD (or ampBCD) 404 illustrated onthe right of FIG. 4 includes a single cooled cold plate 412 shared bythe OBD and DC-DC packaged in the same enclosure.

FIG. 5 provides an external view of an exemplary BCD 500. There are atleast two high voltage connectors like the Tyco TE line with built-inHVIL for the charge connector 502 and HV out 504. There are three 12Vterminal posts for 12V in 510, 12V out A 512, and 12V out B 514. We alsohave coolant in/out connections 516. Furthermore, for vehicles withmultiple inverters or other high voltage loads, additional outputs canbe added (FIG. 5).

FIG. 6 provides a semi-transparent view of the BCD 600. There are twoboards packaged. One contains the OBC board 602, the other is the DC-DCboard 604. The controller can live on either board 602, 604. A ribboncable (not shown) can wrap around the cold plate 606 and handle anyboard to board communications (FIG. 6).

As illustrated in FIG. 7, one bus bar of the contactors 702 used forfast charging can also be thermally coupled to the cool plate 704. Thethermal coupling of the electrical devices to the heatsink (bus bars,current sensor, and power transistors can be made using the LOCTITE 315self-shimming adhesive, suitable for bus voltages up to 1000V, orequivalent (like thermal gap pads). FIG. 8 provides a different view ofthe same coupling between the contactor bus bar 702′ and cool plate704′.

Further, when the large power magnetic components 902 are woundutilizing a square profile wire, as illustrated in FIG. 9, the powermagnetic components can be thermally coupled to the heat sink.

In addition to a reduction in the number of components, the amount ofmaterial required for the enclosure is reduced compared to theindividual enclosures required for a distributed system.

Another aspect of the disclosure relates to thermal management. Thecooling system complexity is reduced by having less hosing andheat-sinking between multiple ECUs. For example, the on-board charger,dc/dc converter, and ampSwitch can all benefit from the same coolingsystem. Other components such as the current sensor also benefit fromadditional cooling which results in increased state of charge accuracyby means of higher accuracy current sensing. The mechanical BOM is shownbelow in Table 5.

TABLE 5 Mechanical Items Equivalent Mechanical Part BOM NumberDescription Cold Plate Custom Two aluminum pieces that are cast andsealed with a gasket. Channels exist to pipe coolant through. Channelwidth is designed to reduce Eddy currents via best CFD practices. OBCPCB Custom DC-DC PCB Custom Ribbon OTS Connects the two boards togetherCable iSense A, B, Customer Manginin and copper mounted against cold-LBB and plate bonded by bolt and electrically HVB insulated by Loctite315 or gap pad FC Tyco LEV- This a downsized contactor that normallyContactors 100 or supports 100 A continuous current. By equivalentcooling a bus bar connected to the contactor, we have now cooled thecontacts and continuously drive current at a much higher value than itis rated for. Magnetics Custom Using square wire, thermally bonded toheat sink. The heat sink can have an optional cut-out so the magneticscan sink into the cold-plate/heat-sink. HV TE Connec- HV Connectors withbuilt-in HVIL Connectors tivity PN 1-2293575-1 12 V terminal lug post LVSealed for low voltage communications and connector signal ground

The above embodiments can provide the following technical advantagesover existing systems:

-   1. Integration of one or many of the following components and/or    functions into a single box reduces over-all packaging volume and    weight and cost: HV junction box, HV-BMS, OBC, Current Sense,    Isolation Switch, PTC, DC/DC, LV-BMS, Fast Charge Contactor Control,    CCS/CHAdeMO/J1772/ISO15118/PLC/GBT Charge Controller. This packaging    advantage reduces wiring connectors, HV access points, EMI    components, power supplies, FR4, processors, communication    transceivers and other electrical components and plumbing and    coolants connections, coolant power requirements,    cold-plate/heat-sink casing material mass.-   2. Thermally managed current sensing for increased SOC accuracy.    Typically, as the current sensor heats and cools the accuracy goes    down. By placing the BMS in the BCD, we already have a cold plate    and an easy means to thermally stabilize the shunt which increases    its accuracy and leads to an improved SOC estimation over    traditional designs. Some other designs use a flux-gate or    hall-effect sensor to avoid the thermal drift problem of shunts.    However, these sensors are tall and do NOT package well.-   3. Low voltage vehicle battery BMS implemented with lithium-ion or    lead-acid battery technology is inherent in the Switch design and    basically becomes a software component. This eliminates an external    IBS mounted in the vehicle usually at the 12V battery terminals.-   4. Smaller fast charge contactors through heat-sinking one bus bar    through the cold plate/heat sink.-   5. Bi-Directional DC/DC provides fails safe limp mode through BMS    detection by powering the drive from 12V. This is enabled by combing    the HV and LV BMS. This capability is abstracted to the rest of the    vehicle, enabling this feature to be seamlessly developed reducing    NRE.-   6. Dual or more 12V busses powered off one DC/DC reduces volume,    weight and cost and achieves functional safety requirements for 12V    redundancy features for autonomous vehicles or aircraft or any other    electrical system that needs safety critical 12V.-   7. Reduced overall vehicle cold-plate/heat-sink mass/volume knowing    that the OBC and the DCDC will never be fully on at the same time.-   8. Maximizing drive power without over-discharging battery bricks by    directly sensing motor current, HV battery current and drive limits    algorithm in the BMS by sensing the pedal. This is achieved through    low latency measurements which cannot happen through typical CAN and    isoSPI busses.-   9. By integrating a low voltage BMS and DC-DC, we can protect the    low voltage battery from over-charge in a functionally safe manner    without adding an additional high-current contactor, which is    expensive and takes space. This is especially important for LV    lithium batteries which are susceptible to fire when overcharged.    The way to stop over-charge is to use a HV over-voltage comparator    at the cell or module level and/or safety rated firmware which    monitors for over-charge. Once detected the gates of the controller    can directly switch off the DC-DC.-   10. Avoid CAN or LIN based current sensors by placing the controller    near all the current sensors, which are now packaged within the BCD.    CAN/Lin based current sensors typically costs a few dollars more (X    several in the system). Since the BCD moves the LV and HV BMS within    a shielded small box, EMI is less of a concern. This allows the BCD    to directly measure across a shunt. Filtering and amplification can    be done as normally employed.-   11. Autonomous vehicles require 12V redundancy for latitudinal and    longitudinal torque required for SAE Level 4 and SAE Level 5    autonomous systems. Traditionally this is achieved by using dual    DC/DC converters which create dual 12V systems. A new invention on    its own, called an isolation switch (made up of a solid-state    switch), can be integrated into the BCD. By integrating this    isolation switch into the BCD, an Intelligent Battery Sensor (IBS)    firmware function will manage the 12V battery with only the cost of    an added current sensor. From the customer's perspective the BCD has    dual 12V outputs without out two DCDCs, significantly lowering the    cost.-   12. Consolidation of high voltage components reduces the total    number of HV access point thereby increasing safety and reliability.    From a safety perspective, there are less high voltage access points    so the complexity of the high voltage interlock loop can be reduced    by combing the OBC and DC-DC in one box. This reduces wiring and    connector cost as well as improving safety and reliability (through    less HVIL connection points). Reliability is improved because    isolation leaks paths and interlock connection points in the system    are reduced.-   13. By managing the LV battery, the LV BMS can selectively choose to    discharge the 12V battery in the case that the heat sink/cold-plate    thermal loads are too high. This keeps cold-plate/heat-sink    under-sized.-   14. When the BCD is plumbed on a common cooling loop with other    systems that require heat (such as a ‘heater core’ to heat the    passenger cabin or to increase the temperature of a battery pack),    the BCD can source heat into the coolant. Power silicon that is    arranged into a power-pole topology presently used in the normal    functionality of the OBC and DC-DC is used to accomplish this heat    generation by driving the power silicon in the linear/ohmic region.    Sources for the heat are either of the N high voltage inputs or the    OBC AC ‘mains’.-   15. The combination of the OBC and the DC-DC into a common physical    package presents a new opportunity to create a single power    electronics topology to service the requirement that both the OBC    and DC-DC provide separately. This is realized by combining the    power magnetics of both converters into a single package. The high    frequency transformer used in the DC-DC is eliminated by adding a    tertiary winding to the transformer of the OBC. Doing this also    eliminates the dedicated power silicon drive circuitry for the DC-DC    transformer. By doing this the DC-DC now has two energy sources,    either the HV battery pack while the vehicle is charging or the AC    ‘mains’ voltage while the vehicle is charging.-   16. By having the integrated BMS sample the cell voltages at the    peak of the waveforms, we can prevent over-charge of the battery    cells. This can only be accomplished in a system when the control    circuitry of both the BMS and OBC are integrated together, as done    here.-   17. By having a bi-directional DC/DC, a precharge relay circuit can    be eliminated save system costs. The bi-directional DC/DC will be    controlled in such away to precharge the inverter and system    capacitors before the main battery contactors will be charged.

What is claimed is:
 1. A controller comprising: a BMS LV moduleconfigured to manage a low voltage battery; a BMS HV module configuredto manage a high voltage battery; a DC-DC module configured to control aplurality of DC-DC FETs; and an ampSwitch module configured to detect ashort on a bus and switch to an open state, and further configured tocommand the DC-DC module or an alternator to match the low battery'svoltage and switch to a closed state when voltage returns to normal. 2.The controller of claim 1, further comprising: an OBC module configuredto control a plurality of OBC FETs or IGBT by referencing a currentsetpoint provided by a wall-power limit and a limit of the high voltagebattery.
 3. The controller of claim 1, further comprising: a PTC moduleconfigured to determine torque limits of a powertrain system to controlboth longitudinal and lateral movements of a vehicle.
 4. The controllerof claim 1, further comprising: an FC module configured to manageopening and closing a plurality of FC contactors.
 5. The controller ofclaim 1, further comprising: an ADC module configured to monitor analogsignals and employee digital filter techniques for signals from at leastone of a current sensor, low voltage battery voltage and temperaturesensor, and pedal monitor position sensor of a brake or acceleratorpedal.
 6. A combined battery management system, charger, and directcurrent converter (BCD) for an electric vehicle, comprising: a maincontroller comprising: a BMS LV module configured to manage a lowvoltage battery; a BMS HV module configured to manage a high voltagebattery; a DC-DC module configured to control a plurality of DC-DC FETs;and an ampSwitch module configured to detect a short on a bus and switchto an open state, and further configured to command the DC-DC module oran alternator to match the battery's voltage and switch to a closedstate when voltage returns to normal.
 7. The BCD of claim 6, furthercomprising a low voltage current sensor configured to measure current ofa low voltage battery of the electric vehicle.
 8. The BCD of claim 7,wherein the low voltage current sensor comprises: a first current sensorconfigured to detect a short-circuit failure of a first 12V busconnecting the BCD to the low voltage battery; and a second currentsensor configured to detect a short-circuit failure of a second 12V busconnecting the BCD to the low voltage battery.
 9. The BCD of claim 7,wherein the low voltage current sensor comprises a fuse and contactor.10. The BCD of claim 6, further comprising an OBC; and wherein the maincontroller further comprises an OBC module configured to control theOBC.
 11. The BCD of claim 10, wherein the OBC comprises a plurality ofOBC FETs or IGBT; and wherein the OBC module controls the OBC byreferencing a current setpoint provided by a wall-power limit and alimit of the high voltage battery.
 12. The BCD of claim 11, wherein theOBC is a bi-directional OBC.
 13. The BCD of claim 11, wherein the OBC isconnected to a charge connector of the electric vehicle.
 14. The BCD ofclaim 6, further comprising a single direct current converter (DC-DC)configured to charge the low voltage battery from a high voltagebattery.
 15. The BCD of claim 6, further comprising an ampSwitchcomprising back-to-back FETs, the ampSwitch controlled by the ampSwitchmodule of the main controller.
 16. The BCD of claim 6, furthercomprising a high voltage current sensor configured to measure currentof a high voltage of the electric vehicle.
 17. The BCD of claim 6,wherein the main controller further comprises: a PTC module configuredto determine torque limits of a powertrain system to control bothlongitudinal and lateral movements of a vehicle.
 18. The BCD of claim 6,wherein the main controller further comprises: an FC module configuredto manage opening and closing a plurality of FC contactors.
 19. The BCDof claim 6, wherein the main controller further comprises: an ADC moduleconfigured to monitor analog signals and employee digital filtertechniques for signals from at least one of a current sensor, lowvoltage battery voltage and temperature sensor, and pedal monitorposition sensor of a brake or accelerator pedal.